1. Field of the Invention
The present invention relates to a decorative material having a pattern formed on its surface, and, more particularly, to a patterned decorative material having uneven surface gloss that makes the pattern impressive, the surface of the decorative material including the pattern being excellent in durability.
2. Related Art
A decorative material is produced, for example, by printing a pattern on a substrate, or by coating a substrate with a proper material, or by imparting unevenness to a substrate, and used for the interior or exterior finishing of buildings, for the manufacturing of furniture, or the like. For the substrate, a proper material is selected from board-type materials such as wooden boards, metallic plates and slate boards, and sheet-type materials such as paper and plastic films, depending on the intended use of the resulting decorative material.
In the case where a pattern is formed on a substrate by means of printing, greater effects of printing are obtained when a sheet-type substrate is used. Moreover, even if a large number of sheet-type substrates are handled at one time, they do not become bulky unlike board-type substrates. Sheet-type substrates are therefore often used for producing decorative materials. The term xe2x80x9cdecorative materialsxe2x80x9d herein used include both decorative laminates produced by the use of board-type substrates, and decorative sheets produced by the use of sheet-type substrates.
In the production of decorative materials, it is also important to impart texture to them. For this purpose, there have been proposed various methods for delustering or roughening the surface of a decorative material, in which delustering or roughening is conducted so that the delustered or recessed parts of the surface will coincide with specific parts of a pattern present on the decorative material. By the use of these methods, it is possible to obtain decorative materials having patterns that appear to be more realistic to the surface of natural wood board.
Japanese Patent Publication No. 41364/1976 discloses a process for producing a veined decorative material whose surface has uneven gloss or roughness. This process comprises the steps of preparing three or more ink compositions by gradually increasing granular solid content; successively forming, on a base sheet, patterns of the winter grain of annual ring, the summer grain of annual ring and vessels in wood by the use of the ink compositions in the order of increasing granular solid content, thereby forming a pattern of the grain of wood; and applying a coating material to the entire surface of this pattern to form thereon a coating film that can serve as a surface-protective layer. According to this process, a larger part of the coating material applied penetrates into a pattern that has been formed by using an ink composition having a higher granular solid content, so that uneven gloss or roughness is imparted to the surface of the decorative material.
The production process disclosed in the above-described patent publication has the following drawback. As shown in FIG. 2, a coloring layer 3 and a pattern layer 4 that are usually formed on a substrate 2 are covered partially with a highly permeable pattern layer 6 containing granular solid components. Moreover, the coloring layer 3 and the pattern layer 4 contain granular solid pigments, and a pattern included in this pattern layer is formed discontinuously. Therefore, in the case where an absorptive/permeable material such as paper or non-woven cloth is used as the substrate 2, even those parts of a surface-protective layer 7 that are not right above the pattern layer 6 are recessed below the surface and become more or less mat because of the undesirable absorption of the surface-protective layer 7 by the substrate 2, although these parts should be glossy or form non-recessed parts 8xe2x80x2. For this reason, the differences in surface gloss or in level of the surface between those parts of the surface-protective layer that are right above the pattern layer 6 and the other area become small and obscure.
Further, in the production process disclosed in the above patent publication, a hardening polyurethane resin is used for forming the surface-protective layer, while ink compositions containing as their binder a mixture of nitrocellulose and alkyd, or polyamide resins are used for forming the patterns. The adhesion between the surface-protective layer and the pattern layer is therefore insufficient. Moreover, special regards are not paid to the solvent resistance of the surface of the decorative material, including the pattern. If no efforts are made to increase the adhesion between the two layers, when an adhesive cellophane tape is adhered to the surface of the decorative material and then peeled off, the surface-protective layer tends to be separated from the decorative material along with the adhesive cellophane tape. Further, if no efforts are made to improve the solvent resistance of the decorative material, there is such a possibility that, when the decorative material is wiped with a cloth or the like impregnated with a solvent, the layers constituting the decorative material is successively removed, and the pattern is exposed and finally erased.
Although there are a variety of physical or chemical requirements in the field of decorative materials, it is essential that patterns formed on decorative materials remain under any condition. If the patterns disappear, the decorative materials cannot fulfill anymore their original function of decorating objects to which they are adhered, even if the base sheets remain.
An object of the present invention is to provide a patterned decorative material whose surface has deep and sharp recesses or distinguishable delusterings corresponding to specific parts of the pattern. Another object of the present invention is to provide a patterned decorative material having, in addition to the above feature, excellent solvent resistance so that the pattern is not easily erased even when the surface of the decorative material is wiped with a cloth or the like impregnated with a solvent.
In the present invention, the surface of the decorative material produced is covered with a surface-protective layer of an ionizing radiation hardening resin composition excellent in both physical and chemical properties. The aforementioned problems can be solved by forming a coating film capable of preventing the ionizing radiation hardening resin composition from penetrating into the underlying layers, and by providing, on top of this coating film, a pattern layer having permeability for the ionizing radiation hardening resin composition higher than that of the coating film.
The present invention relates to a decorative material comprising an absorptive/permeable substrate, and a surface-protective layer made of a film of an ionizing radiation hardening resin composition that has been hardened by crosslinking. An even and uniform penetration-preventing coating layer, which has a low permeability for the ionizing radiation hardening resin composition, is provided between the substrate and the surface-protective layer, covering the entire surface of the substrate. A highly permeable pattern layer made from a resin including a filler, which has a permeability for the ionizing radiation hardening resin composition higher than that of the penetration-preventing coating layer, is provided on the penetration-preventing coating layer. The surface-protective layer has recesses and/or delusterings at right above the highly permeable pattern layer.
In the present invention, it is preferable that both the penetration-preventing coating layer and the highly permeable pattern layer be made of films of hardening resins, hardened by crosslinking.
Further, it is also preferable that the penetration-preventing coating layer be made from a polyurethane resin obtained by crosslinking an unsaturated polyester urethane polyol with an isocyanate for hardening and that the surface-protective layer be made of a film of prepolymers, oligomers and/or monomers of (meth)acrylate that has been hardened by crosslinking.
Further, in the present invention, it is preferable that the penetration-preventing coating layer be mat. Furthermore, it is preferable that another pattern layer be laminated to the surface of the substrate or that an even and uniform coloring layer and another pattern layer be laminated to the surface of the substrate in the order mentioned.
In the present invention, a surface-protective layer made of a film of an ionizing radiation hardening resin composition that has been hardened by crosslinking is provided so as to cover an absorptive/permeable substrate; and, under this layer, a highly permeable pattern layer having high permeability for the ionizing radiation resin composition that is used for forming the surface-protective layer is formed, and, under this pattern layer, a penetration-preventing coating layer is provided. Therefore, those parts of the surface-protective layer that are right above the highly permeable pattern layer are recessed below the surface and/or delustered, and, at the same time, have decreased gloss because the ionizing radiation hardening resin composition penetrates into the highly permeable pattern layer, while the other area does not undergo recession or decrease in gloss because the penetration-preventing coating layer prevents the ionizing radiation hardening resin composition from penetrating into the underlying layers. For this reason, even when an absorptive/permeable material such as paper is used as the substrate, it is possible to produce deep and sharp recesses on the surface of the decorative material, corresponding to specific parts of the pattern formed on the substrate.
In the present invention, since both the penetration-preventing coating layer and the highly permeable pattern layer are made of resin films hardened by crosslinking, the decorative material shows high solvent resistance; these layers are not easily removed even when the surface of the decorative material is wiped with a cloth or the like impregnated with a solvent. In addition, since the entire surface of the absorptive/permeable substrate is coated with the penetration-preventing coating layer, unfavorable absorption/permeation of the surface-protective layer by the substrate does not occur at an area where the highly permeable pattern layer is not formed. Therefore, the differences in level of the surface and in surface gloss between the parts right above the highly permeable pattern layer and the other area are more emphasized and become clear.
Further, in the present invention, since the surface-protective layer is formed by the use of a coating composition including a material having (meth)acryloyl group such as a prepolymer of (meth)acrylate, and the penetration-preventing coating layer is formed by the use of an unsaturated polyester urethane polyol and an isocyanate, the (meth)acryloyl group contained in the surface-protective layer chemically combines with the unsaturated polyester moiety in the penetration-preventing coating layer to increase the adhesion between the two layers, and to impart, to the resulting decorative material, improved resistance to abrasion with steel wool and also to solvents.
Furthermore, according to the present invention, it is possible to provide a mat decorative material excellent in durability by making its penetration-preventing coating layer mat. Furthermore, according to the present invention, it is possible to provide a more decorative decorative material by using a substrate to which another pattern layer has been laminated. In addition, according to the present invention, it is possible to provide a still more decorative decorative material by using a substrate to which an even and uniform coloring layer and another pattern layer have been laminated in the order mentioned; such a decorative material is free from color shading even if the substrate itself has color shading.